Friday, April 30, 2010

GSFC - April 30, 2010 - 800 million years ago an impactor struck the eastern extent of Oceanus Procellarum, the "Ocean of Storms." The bright-rayed crater Copernicus was formed: the crater now considered representative of many lunar craters created during the Copernican period on the Moon.

Copernicus crater is 93 km wide. LOLA data reveals that its crater rims reach almost 300 m above the lunar mean elevation level, while its floor rests near -1700 m. The blue areas contained within the interior purple of the impact crater in this LOLA image reveal Copernicus's three central peaks.

Spacing between tracks of LRO orbits is larger near the equator than the poles. This spacing leads to greater interpolation of equatorial data and lowers the resolution of LOLA images, including this image of Copernicus, created in this region of the Moon.

Wednesday, April 28, 2010

Close up of a northwest trending wrinkle ridge in the high-Titanium basaltic lava plains of Mare Tranquillitatis, near a Constellation region of interest. The bright areas of along the steepest parts of the ridge are places where less mature subsurface materials have been exposed by small impacts or fracturing of the bedrock as the original mare surface buckled. (1.25 km wide area from LROC NAC M104376385L; Orbit 542, August 8, 2009; alt. 123 km) [NASA/GSFC/Arizona State University].

The Constellation region of interest in Mare Tranquillitatis is a good example of a site that combines operational benefits with fascinating geologic features. An equatorial nearside location where landings would be fairly straightforward, the most obvious feature that draws your eyes in this Region of Interest is the dramatic wrinkle ridge that dominates the landscape. Wrinkle ridges like these are common on lunar mare surfaces and have long been a subject of interest to lunar scientists.

Long wrinkle ridges in Mare Tranquillitatis in LRO Wide Angle Camera (WAC) image M117345275M. The section of wrinkle ridge shown in the featured NAC image is in the center of this WAC view. Arago crater (lower left), is 26 km in diameter. Above it is Arago Alpha, one of two extensive 20 km lava domes in the vicinity of Arago familiar to Earth-bound observers when the long shadows of the terminator sweep through the area 5 days after each New Moon or 4 days after a Full Moon [NASA/GSFC/Arizona State University].

Lunar wrinkle ridges can be hundreds of kilometers long, tens of kilometers wide, and hundreds of meters high. (Read more in Wilhelms, 1987) They can have a sinuous or linear appearance with asymmetric cross-sections. In other words, the feature that you see could easily be made up of a smaller ridge superposed on a broad rise.

Lunar wrinkle ridges are found in the mare basalt deposits that filled the giant impact basins on the Moon. Frequently, wrinkle ridges are oriented concentric to large impact basins. Loading of the basin floor with multiple eruptions of mare basalts causes the formation of wrinkle ridges in the basin center and graben along the mare margins (see figure below). The tremendous weight of the newer basalt layers then causes the center of the basin to sag. As the basin center sags, the basalts slide towards the basin center causing compression that results in folding and faulting of the basalt. The sagging of the basin under the weight of the basalt also causes the opening of graben along the edges of the basalt layers.

Idealized cross-section through an impact basin that filled with three episodes of mare basalt eruptions [Hiesinger, 1999, PhD dissertation]. Loading of the basin floor with mare basalts causes the formation of wrinkle ridges in the basin center and graben along the mare margins.

We also know, thanks to the samples collected by the Apollo 11 astronauts, that the mare basalts in this region are rich in titanium. Study of the Apollo samples has shown that it is relatively straightforward to extract resources (especially oxygen) from titanium-rich lunar soils. Using local resources will increase the capability and reduce the cost of future lunar exploration.

Tuesday, April 27, 2010

It might seem easy to spot after cameras on-board the Lunar Reconnaissance Orbiter (LRO) found Lunokhod 1 late last year. Nevertheless, after years of searching, before last November little hope remained that it's French-built laser reflectors would ever assume their important place with four other reflector stations on the Moon. With the help of LRO researchers have now acquired a reflection, tallied in photons, from the old Russian vehicle, a big bonus for theoretical cosmology and planetary science. In the images above and below Lunakhod 1 is set within the context of true surroundings. Above, a high ridge is visible on the north-northwest horizon, beyond the flat vastness of Mare Imbrium. These are the foothills southwest of Promontorium Heraclides. The closest of these are about 42 kilometers away. Click here for a better look.

Can you find Lunokhod 1 in the top image, maybe from clues in the enhanced close-up below it? The Russian lunar rover parked on the western shore of Mare Imbrium hadn't been detected since September 1971. More important than just locating Lunokhod 1, with the essential help of the LROC team at Arizona State, researchers very recently detected it's French-built laser range reflector. LRO (LROC) Narrow-Angle Camera M114185541RE (Orbit 1961, November 30, 2009, alt. 48.4 km. & resolution = 51.3 cm per pixel.) [NASA/GSFC/Arizona State University].

Researchers at the University of California at San Diego have acquired a reflection from the Laser Range Retro-Reflector on Lunokhod 1, the Soviet lunar rover that went missing from September 1971 until being found last November through the narrow-angle cameras on LRO.

The addition of a fifth working laser reflector is a windfall for physicists who believe measuring an even finer Earth-Moon distance could solve important puzzles about the cosmos, things like the locality of physical laws, for example. Putting a point on the Earth-Moon distance finer than three centimeters is thought to be the key.

As early as December 1969 McDonald Observatory gauged the Earth-Moon distance to within 30 centimeters by timing reflection of laser light to and from the Apollo 11 landing site. A pencil-thin laser beam is a kilometer-wide after a 1.5 light-second trip to the Moon. The LRRR deployed at Tranquility Base was designed to reflect light precisely in the direction from which it arrives. After an additional 1.5 seconds the laser light returned to Earth is measured by the photon, enough over many sessions to measure Earth-Moon distance with great precision.

An additional LRRR, identical to the one at Tranquility, was deployed at Fra Mauro by Apollo 14 and another, four-times larger than these, was set up north of the equator near Hadley Rille by Apollo 15. The latter, deployed in 1971, is still the most reliable of the LRRR's set up during the Apollo era.

The Soviet Union landed two RTG-powered lunar rovers, in 1970 and 1973, and both Lunokhod 1 and 2 were equipped with smaller French-built LRRR's. After ten months of successful operation the Soviets lost contact with Lunokhod 1 in 1971. Despite problematic thermal issues and limitations due to its smaller size the LRRR on Lunokhod 2, parked on the eastern side of Mare Serenitatis, has been periodically detected since its mission ended in 1973.

Lunokhod 1 was thought to be parked properly, to the west of it's carrier landing site near the western edge of Mare Imbrium. Instead it appears the rover was properly parked to the north of its last known location, enough for a wide miss. No confirmed detection of its LRRR had been cataloged in over 39 years, until now.

Laser Range Retro-Reflector array at the Moon. Apollo 11 (1969) & Apollo 14 (1971), near the equator and 27 degrees of longitude apart, each one quarter the size of the unit deployed by Apollo 15 (1972). Not detected until 2010 is the french-built triangular array on the Soviet rover Lunokhod 1. The design repeated on the Lunokhod 2 robotic rover has experienced "thermal drawbacks" that hinder daylight detection, conversely sometimes aiding its detection during the lunar night. In addition, NASA/Goddard Space Flight Center is presently keeping close track of LRO using laser ranging from a telescope in Maryland.

In 2005 McDonald Observatory shut down its laser and U.S. work moved to the more powerful and more sensitive system at the Apache Point Observatory in New Mexico. As work has progressed there, high hopes have been held that, at last, Lunokhod 1 might be added to the network. With the help of LRO, which swept up the definite location of the long-lost Soviet rover last November, four decades of patience have been rewarded.

Read Monday's University of California/San Diego news release through the report from NASA's Astrobiology Institute, HERE.

Monday, April 26, 2010

Geologist, former U.S. Senator and the only professional scientist to visit the Moon, Dr. Harrison H. Schmitt spells out his specific concerns to Congress regarding proposed changes to American space policy.

The President announced a "bold approach for space exploration and discovery," to quote the White House. In considering his FY2011 budget proposals for NASA, Congress rightly should ask just how "bold" is this approach vs what America requires in the intense geopolitical environment of space.

In addition, Congress should ask for specifics as to why this approach would be better than the Constellation program already approved by Congress, and whether it truly "Advances America's commitment to human spaceflight and exploration of the solar system," to again quote the White House. Congress also should question if the proposals support the primary constitutional rationale for funding NASA, that is, as a contribution to "the common Defence."

The current United States space policy, twice approved by the Congress in response to President George W. Bush's FY2005 and subsequent budget requests, calls for focused technology development and mission formulations that would 1) enable a return to the Moon not later than 2020; 2) be consistent with future Mars exploration; 3) complete the construction of the International Space Station; and 4) replace the Space Shuttle with a new crewed vehicle not later than 2014.

The Constellation program's design would achieve these goals subject to the projected run-out funding for NASA in that original FY2005 budget.

Unfortunately, the Bush White House submitted annual budgets for FY2006-10 that funded Constellation $11 billion less than originally deemed necessary to maintain the proposed schedule. This includes the effects of an Office of Management and Budget error of about $3.8 billion in 2004 budgeting for the run-out cost of the Space Shuttle. Congress exacerbated this continued under-funding for Constellation through inflation-related cuts of about $1.5 billion in its 2006 and 2008 Continuing Resolutions.

In spite of these budgetary complications amounting to under-funding of some $12.5 billion over six years, and contrary to the Augustine-Crawley Commission's allegations, Constellation remains "executable" albeit with some delay relative to the original schedule. The Augustine-Crawley Commission did not look at the reality of the existing Constellation program and its previously approved funding, but constrained itself to the cumulative cuts of $28 billion for FY2010-20 submitted in the Obama budget for FY2010. Clearly, Constellation would not be "executable" with such drastic cuts to the original funding plan.

New funding of about $3 billion per year for the next five years would maintain the current schedule for Constellation and possibly remove dependency on Russia in 2014 for Space Station access (NASA's FY2010 budget of $18.3 billion is about 0.5 percent of total federal spending.). If this budgetary adherence to current space policy were undertaken, the United States could indefinitely maintain its dominant position as the world geopolitical and technical leader in space.

With this six-year long period of intense design and development already behind us, President Obama's budget proposals would stop Constellation and substitute the following policy elements:

1. A NASA budget increase of $6 billion over five years. These new dollars would be used largely to increase expenditures for space, Earth, and climate science. (This same $6 billion increase, if dedicated to Constellation, would give the U.S. its own Orion spacecraft and Ares launch vehicle for access to Space Station.)

2. A "commitment to decide in 2015" on a specific approach to a heavy-lift rocket. Such a launch vehicle would be required if future policy added flights to "lunar orbit, Lagrange Points, Asteroids, moons of Mars, and Mars." (With no commitment to any specific objective for new heavy-lift, this policy position is made to order to be abandoned. It contains the technically and philosophically ludicrous suggestions that Lagrange points could be fuel depots, without getting fuel from the Moon, and that a mission to an asteroid has greater historical value than a base on the Moon.)

3. Technology development and test to increase space capabilities and reduce costs. The objective would be to "establish the technological foundation for future crewed spacecraft for missions beyond Earth-orbit." (As with heavy-lift, the policy gives no focus for these technology efforts as valuable as they could be, particularly with the development of a domestically produced, large hydrocarbon fueled rocket engine like we had for Apollo. Claims of providing "more jobs for the country" are disingenuous, however, as many more thousands of jobs would disappear with the cancellation of Constellation and the retirement of the Space Shuttle.)

4. A "steady stream of precursor robotic exploration missions." (A steady stream of such missions has been underway for two decades so this is nothing new.)

5. Restructuring of Constellation with the Orion spacecraft downsized to an emergency escape vehicle for the Space Station. (Orion development has progressed to the point that this proposal amounts to its termination and the start of a new spacecraft program that will cost more that completing Orion. Contrary to White House claims, this logically does nothing to reduce dependence on Russia to carry Americans to the Space Station. Major additional costs would be incurred to fly the new Orion to the Station and replace it periodically.)

6. An increase in "astronaut days in space by 3500 over 10 years." (No obvious means of doing this exist based on available Russian Soyuz flights to the Space Station and current biomedical limits on crew exposure to the space environment.)

7. A "jumpstart" to non-NASA, "commercial space launch" capabilities for human space flight. (With no known business case that would justify referring to such a capability as a "commercial" venture that private investors would support, and no definition of the final level of requirements and specifications NASA ultimately would demand, this fully subsidized initiative amounts to another, probably under-funded program by government. It is not clear how much funding will be requested for this subsidy, but a total of about $3 billion of new money each year over ten years would keep Constellation on track for a 2014 availability of Orion and a 2020 return to the Moon.)

8. Placing the space program on a more ambitious trajectory. (Clearly, the President's proposals are not as ambitious as the Constellation return to the Moon/Mars exploration program. Rather, the President takes American human space flight out of the calculations of other nations.)

Although many inherent logical, technical, and implementation flaws in the Obama policy are evident, it is important to examine the consequences for the United States if the President's promises could be kept in their entirety:

1. The United States' human space flight capability will rapidly atrophy and then disappear by about 2020. With this atrophy would come the disappearance of the psychological geopolitical edge from which we have benefited immensely since World War II and particularly since Neil Armstrong stepped on the Moon.

2. China will control lunar resources for terrestrial energy and space flight as well as dominate the Settlement of the Moon and eventually Mars. China repeatedly expresses interest in harvesting helium-3 fusion fuel present in the Moon's surface materials. A lunar settlement, sustained by the by-products of helium-3 production, constitutes the most cost and politically effective means of gaining this critical future energy resource.

If the Moon comes under China's control, long-term geopolitical reality would be changed in the same way that the Middle East's control of oil dominates our current national security vulnerabilities.

3. Russia will control access to the International Space Station. Prices per astronaut visit to the Station, including the astronauts of our non-Russian partners, will escalate from the $50 million today to whatever the traffic will bear. After the Space Station must be abandoned due to aging, probably no later than 2025, any future station will be left to China and/or Russia to build, crew, and use.

4. Europe, Japan, and other nations with limited space capabilities will cut deals for space access with China and Russia. A clear loss of international interest in space and other partnerships with the United States will result.

5. Without a clear set of space objectives, NASA will be reduced to a Space Science Agency. Past strong technical and professional synergism with national security will disappear.

6. Subsidized human space flight development for national space projects will see cost escalation and schedule slips. If this nebulous alternative to traditional NASA contracting received adequate funding, including needed reserves, then this potential problem might disappear; but, since Apollo, that is too much to expect in modern federal budgeting. Inevitable cost and schedule problems will follow inadequate initial funding, unanticipated or unknown technical issues, requirement and specification creep, and progressive NASA intrusion into design and implementation. As taxpayer dollars will fund this effort, cost increases will be driven by the unfortunate and overly risk-adverse nature of mainstream media reporting, and political reactions by the Congress, White House, and NASA bureaucracy.

7. Inevitable shrinkage and loss of innovation of the aerospace and defense industrial base will occur. Combined with the Administration's and Congress' unconstitutional under-funding of advanced research, development, and testing for national security systems, the lack of funding and focus on specific space objectives will worsen this progressive weakening of our essential development and manufacturing foundations.

8. Engineering and science education and research will lose another major stimulus. The governmental and academic establishments continually underestimate the importance of national human space flight initiatives in stimulating academic education and research; but it is nonetheless still as real in the minds of young people today as it was after the launch of Sputnik in 1957.

In the light of these obvious adverse consequences even if all the President's promises are kept, and much worse if any are not, why would the President not just budget to properly fund and manage Constellation?

Compared to trillions of dollars of other spending he has asked for, this would have added a relative pittance. Would not President John Kennedy, or Presidents Eisenhower, Johnson, and Reagan, have moved forward in space rather than backward, given the global challenges we face?

The depth of the current Administration's antagonism toward the historical vision of America, as well as toward a preceding President, is unprecedented. The philosophical wedge driven between citizens and their government reaches deeper than any time since just before the Civil War. Our national future on Earth, as well as in the ocean of space, requires that this negative view of America, its people, and its future be overturned in upcoming elections.

Harrison H. Schmitt is a former United States Senator from New Mexico as well as a geologist and former Apollo Astronaut. He currently is an aerospace and private enterprise consultant and a member of the new Committee of Correspondence.

Saturday, April 24, 2010

LROC Narrow-Angle Camera (NAC) closeup of clustered craters on the lip of the Schrödinger pyroclastic cone, one of the NASA Constellation Regions of Interest (ROI). Although believed to be relatively young, these craters have a subdued appearance, a texture smoothed by micrometeor 'gardening' typical of older lunar surfaces) because they formed in loose pyroclastic material. NAC FrameM108313384R, this view is 785 meters across [NASA/GSFC/Arizona State University].

How old is the Moon? How old are the craters and basins, and the dark mare that fills many of them? When did lunar volcanism begin and end? These and many other questions about the Moon have been asked for millennia, and one of our best means for answering these questions is by simply counting the number impact craters on a particular feature.

This NAC frame (785 m across) shows a cluster of small impact craters on the rim of a cone-shaped pyroclastic deposit in the floor of Schrödinger Basin. The largest crater in the view is about 690 meters across. Schrödinger Cone is one of the largest single-vent formations yet observed on the Moon; crater counts by Eugene Shoemaker, et al. (1994) suggested it may be less than a billion years old -- ancient but still young by lunar standards!

Mosaic of Clementine (1994) UVVIS (ultraviolet-visible spectrophotometry) images (750-nm band) of Schrödinger Basin (312 km diameter). In addition to the prominent, darker cone-shaped feature (arrow) Schrödinger has an inner ring of mountains partially encircling the basin floor (a ‘peak ring complex’) and a network of radial and concentric fractures. The cone is a likely volcanic vent situated on a northeast trending floor fracture, and it has a 4.5 km x 8.6 km vent surrounded by dark, explosively emplaced (pyroclastic) material and a low rim. The Schrödinger Vent is one of the most distinctive single-vent cones observed on the Moon, resembling the ‘dark halo craters’ like those on the floor of Alphonsus. Projection is polar stereographic, centered at -75.0°S, 132.0°E [NASA/DOD/LROC/ASU].

Impact cratering is one of the few processes affecting all planetary surfaces, including the surface of our own Earth. To understand the relative ages of craters, basins, and surface deposits on the Moon, we study its impact craters. More specifically, we count the number and measure size, shape, and distribution of craters and compare those from place to place on the Moon.

We know that older surfaces have more craters (because they have been exposed to impacts for longer than younger surfaces) and we’ve learned that over time newer craters begin to erase the older ones. We call this ‘equilibrium’. If we relate our crater counts to models of the number of things (such as meteors, asteroids and comets) roaming around in space available to create those craters, we can begin to understand the relative ages of features and units on the Moon. Such relative ages have been tied to real or absolute ages at the few sites from which samples have been returned by the Apollo and Luna missions.

Studies of lunar impact craters have worked well in areas such as ‘typical’ mare and highlands units where the properties of surface soils and rocks are reasonably well understood. Are crater counts reliable on pyroclastic deposits, where the soil is formed from loose, relatively unconsolidated ash. Craters formed in such material can appear older than they are because they tend to be shallower, with lower rims and subdued ejecta blankets. The loose material in a pyroclastic deposit appears to both alter the original appearance of an impact crater and make the process of degradation more efficient. This means that craters disappear faster than they do on harder surfaces, such as the mare basalt. If corrections for the type material that craters form in are not applied, then relative age estimates are in error. Such is likely the case with the craters in this cluster on the rim of the volcanic cone in Schrödinger basin.

Crater counts for the region around and within Schrödinger basin by Shoemaker et al. (1994) indicate that it is likely the second-youngest basin on the lunar surface. Schrödinger and its interior deposits are of interest in future lunar exploration in part because pyroclastic deposits have economically valuable components such as iron and titanium.

Moving north (top) in a polar orbit, Japan's Kaguya took extensive HDTV of the lunar far side, including this still showing the Schrödinger Basin interior. The low and relatively darker profile of the pyroclastic dome encircling the vent is right (east) of the image center [JAXA/SELENE].

Before LOLA, the most detailed laser altimetry of the Moon's topography was barely a year-old, gathered using the LAT instrument package on Japan's first lunar orbiter SELENE-1 (Kaguya). Apollo Basin is nearly a quarter the width the vast 2100 km (4 billion year-old) South Pole-Aitken Basin, or 'SPA.' A very deep impact within a deep impact, recent analysis of the deepest interiors of Apollo has uncovered remnants of the Moon's original global crust [JAXA/SELENE].

Apollo Basin has been featured in the news recently (See "'Biggest, deepest crater,' an excavation of the hidden, ancient Moon," March 6, 2010), with discoveries of crustal material previously unseen on the lunar surface. When used with datasets from other instruments (such as M3 from Chandrayaan-1) high-resolution topographic data from LOLA can help scientists understand the extent of this previously unseen lunar crustal material.

Wednesday, April 21, 2010

Early in the first of three EVA's on the Cayley Plain terrain between North Ray and South Ray crater immediately northwest of the Descartes Formation, Apollo 16 lunar module pilot Charlie Duke suggested the lighting and backdrop, including the U.S. flag and "Stone Mountain" beyond was a beautiful photo opportunity. After a moment of hesitation, the famously sedate Cmdr. John Young jumped up and Duke took this now-famous image [NASA/ALSJ]. As cataloged by Eric Jones in the indispensable Apollo 16 Lunar Surface Journal:

"120:25:42John Young jumps off the ground and salutes for this superb tourist picture. He is off the ground about 1.45 seconds which, in the lunar gravity field, means that he launched himself at a velocity of about 1.17 m/s and reached a maximum height of 0.42 m. Although the suit and backpack weigh as much as he does, his total weight is only about 65 pounds (30 kg) and, to get this height, he only had to bend his knees slightly and then push up with his legs. In the (full) background, we can see the UV astronomy camera, the flag, the LM, the Rover with the TV camera watching John, and Stone Mountain. Journal Contributor Joe Cannaday notes that high-point of John's first jump was at a time close to 120:25:49 and the second was almost exactly three seconds later."

Up the slope of "Stone Mountain," near the southern terminus of their second EVA, April 22, 1972, Charlie Duke photographed the bright highlands plain below, all the way to the northern terminus at North Ray and Kiva craters he and Young would visit the following day. In this inset from one in the telephoto panorama, the lunar module is seen from a perspective directly opposite from that seen in the "tourist shots" taken the previous day.

And also through "heavy lenses," from ~50 km overhead (and 37 years after Young and Duke completed their mission), the Descent Stage of their Orion lunar module was imaged in bright lunar mid-day; phase angle = 7.77° (~51.7 cm pp). LROC NAC M113853974LE [NASA/GSFC/Arizona State University].

Thirty Eight years ago today, Young and Duke began emerged on the Cayley Plains of the Moon northeast of Descartes and began three days of exploration. It's a good time to take advantage of the rich legacy of this second to last manned expedition to the Moon by sampling its still-studied science at the Apollo 16 Lunar Surface Journal.

The 'GLXP' is a $30 million competition challenging space professionals and engineers build and operate a wholly privately funded robotic lunar lander. The winning team will complete a series of basic mobility and radio transmission tasks.

Barcelona Moon Team, headquartered in its namesake city in Spain, is among 21 teams from 11 nations vying for a $30 million purse.

Only a handful of humans have ever seen the far side of the Moon. In the future, human explorers near Dante crater in the far side highlands will be searching for samples of the Moon's most ancient, primordial crust (anorthosites like the famous Apollo sample 15415). There was a time after the Moon's formation when the entire surface was covered by an ocean of magma; the upper layer of this magma ocean crystallized to form a global layer of anorthosite.

Since that time, impacts and other geological processes have broken and churned the surface, but this area may posses significant amounts of these original rocks.

Pristine lunar anorthosites are relatively rare in the Apollo sample collections; with enough samples we could learn when the primordial crust started to form and when it was complete. Scientists would also like to learn the rate of cratering during this early period in the Moon's formation. The ancient regolith contains rocks that formed from impact melt, which can be dated to learn when the impact even that created them occurred. Did the large impacts form across a broad range of time - or in one large spike? Collecting samples from this ancient highland area would help use better understand this early period in Solar System development, with profound implications for understanding the early history of Earth.

The Dante region has abundant aluminum and calcium-rich regolith that is available for in situ resource utilization, allowing explorers to extend their stay in this region by processing the local materials to produce oxygen and fuel while building habitats and other structures.

Explorers at this location would never see the Earth. They would instead see the unobstructed vista of the Milky Way above them. The Sun would rise and set once a month, but all communications back to Earth would have to be via orbiting relay satellites. However, with the bulk of the Moon shielding this location from the bright lights and radio waves of the Earth, the central farside highlands are an optimal location for astronomy, especially observations of the low-frequency radio sky.

Monday, April 19, 2010

In our renewed era of lunar exploration, much attention has been given Mare Orientale, which dominates the Moon's western hemisphere, it's "leading edge" facing the forward direction of it's orbit (in relation of the elusive barycenter of the Earth-Moon system - a third of the way to Earth's center). At first glance this latest pretty definitive "false color" crop from the LOLA Image of the Week (centered on 19.9°S, 270°E) might seem little different than that from Japan's SELENE-1 ("Kaguya") and its laser altimeter digital terrain model (DEM). A closer look, plus the time needed to download, shows a lot of information is densely packed in this representation of hundreds of thousands of laser datapoints [NASA/GSFC].

GSFC Only partially visible to Earth-bound observers, a lava-filled target encircled by three mountain ranges peeks over the Moon's western horizon. Orientale, the lunar bull's eye, is considered to be the youngest, most well-preserved multi-ringed impact basin on the Moon. The ring structures surrounding the ~330-km-diameter central mare include the Inner and Outer Montes Rook, each progressively further from the interior basin, followed by the Montes Cordillera (~920-km-diameter).

Over 9 km of elevation are encompassed within Orientale, with the basin floor lying ~3 km below the lunar mean elevation level (R = 1737.4 km), and the western Cordilleras attaining elevations over 6 km above this elevation. The 55-km-diameter Maunder crater, located just south of the northernmost Inner Montes Rook, carves an additional 3 km out of the basin floor, revealing even deeper lunar crustal material at the surface. Lineations radiating from Orientale, likely formed in association with the basin-forming impact event, are also visible in the LOLA altimetry data.

Orientale is of particular interest to scientists because it is filled by a far lesser quantity of mare basalts than other nearside mare basins, leaving more details of its structure and compositional units exposed for scientific investigation.

The view out the window of their impromptu lifeboat Aquarius, the Apollo 13 Lunar Module, less than a day after the Service Module LOX tank explosion that nearly doomed the crew. The time was around sunset, April 15, 1970, back home in Houston, ~398,600 kilometers below. Apollo 13 has just emerged from the Far Side terminator, and the view out from Aquarius, looking past the frosty, crippled Command Module Odyssey is of the long evening shadows of the lunar southern hemisphere, perhaps 15 minutes before reacquisition of signal. During the radio blackout, Apollo became the only manned spacecraft to take full advantage of a free-return trajectory. Apollo Lunar Surface Journal Contributor Danny Caes writes, "The two major craters in this photograph are Chaplygin (just left of center), and Schliemann (below center)." - AS13-62-8885 [ASJ/NASA/JSC]

The longest day for the crew of Apollo 13, for Jim Lovell (on what became his second trip to the lunar vicinity), Rusty Swigert and Fred Haise, had to be when their spaceship combination was traveling it's slowest. That would have been between the explosion, which occurred while they were essentially orbiting the Sun, and their flyover of the Moon's Far Side. During the long uphill climb, still expending velocity from their Earth orbit ejection, Apollo 13 was barely moving a kilometer per second, waiting for the Moon to intercept them.

For a long time, they could watch the Moon approach them in it's orbit. It was also the most anxious time, as the crew and ground controllers "worked the numbers," and they were not promising. Most of the work removing the unplanned and novel uncertainty from their flight plan lay ahead of them.

Fortunately, a lot of what is called "institutional memory," a lot of "head room" was flying with them, at the end of a long radio signal. Nancy Atkinson has been doing such an excellent job cataloging this transformation of near tragedy to triumph, we simply recommend you follow her as she racks it all up for you over at Universe Today.

Saturday, April 17, 2010

The third and final EVA of Apollo 15 brought the astronauts to the edge of Hadley Rille (lower left in this sample swept up by the LROC narrow-angle camera on board NASA's Lunar Reconnaissance Orbiter in polar orbit 47 kilometers overhead, last October). Disturbed regolith is observed along the crater rim at Station 9 and at the edge of the rille at Station 9A. Rover tracks are visible between stations 9A and 10 (and elsewhere). For perspective on the sample above, click here. Sample width represents 520 meters, at 52 centimeters per pixel (LROC NAC M11171816R) [NASA/GSFC/Arizona State University].

The Apollo "J" missions were designed to allow the crews to stay and work longer on the Moon's surface and included a Lunar Rover so they could explore several kilometers away from the Lunar Module. Hadley Rille and the Apennine Mountains provided a dramatic backdrop for the first Apollo "J" mission.

This landing site presented Apollo 15 Commander Dave Scott and Lunar Module Pilot Jim Irwin not only a spectacular view, but access to two key geologic features: a "young" volcanic sinuous rille and "older" highland massifs. These geologic features afforded a chance to sample different events from the Moon's geologic history: early crust formation and late stage volcanism.

Over the course of 3 EVAs (Extra-vehicular Activities), aided by the first of the three lunar rovers Scott & Irwin covered a total distance of ~28 km (17.4 miles), collected ~77 kg (~170 lbs) of lunar samples and spent 18.5 hours exploring the Moon's surface.

A favorite target for earthbound observers, the Hadley River Delta region is contiguous to the Apennine Range, an outer rim of the milestone Imbrium impact event, and source of Palus Putredinis, the "Marsh of Decay," a relatively dark oblique triangle-shaped plain of material on edge of the vast Imbrium basin to the west-northwest. Repeatedly photographed from orbit, modern surveys recommenced with Terrain Camera data gathered by Japan's Kaguya (SELENE-1) orbiter in 2008. That detail, represented in the image above was limited to 5 meters per pixel, insufficient to fully resolve the Apollo 15 descent stage, definitively imaged in 2009 by the LROC team using the narrow-angle camera on-board LRO. [Google Earth v.5].

The LROC Narrow Angle Cameras (NAC) have provided images with 50 cm/pixel resolution of the Apollo 15 landing site. In previous posts, we have shown the Lunar Module descent stage, Lunar Rover, Apollo Lunar Surface Experiment Package (ALSEP) instruments, and darkened paths of regolith disturbed by the crew and the rover. Here, we focus on what the crew accomplished at two locations away from the immediate landing site, accompanied by transcribed voice transmissions describing their discoveries and observations.

Station 7 is at Spur, a 90 meter crater on the slope of the massif to the south known as Mount Hadley Delta. The crew parked along the northeast crater rim (on the downslope side) where they could sample the ejecta blanket. This station is now famous for the collection of "the Genesis Rock," the 4 billion year old sample of anorthosite representative of the original lunar crust. Scott & Irwin's excitement at the discovery is evident in the transcription:

145:42:41 Irwin: Oh, man!145:42:41 Scott: Oh, boy!145:42:42 Irwin: I got...145:42:42 Scott: Look at that.145:42:44 Irwin: Look at the glint!145:42:45 Scott: Aaah.145:42:46 Irwin: Almost see twinning in there!145:42:47 Scott: Guess what we just found. (Jim laughs with pleasure) Guess what we just found! I think we found what we came for.145:42:53 Irwin: Crystalline rock, huh?145:42:55 Scott: Yes, sir. You better believe it.

The Genesis Rock was collected along the rim of Spur at Station 7. The arrow above points to disturbed regolith along the crater rim and rover tracks are visible south of the boulder at Station 6A. This sample from LROC NAC frame M111571816LE is 520 meters in width; north is at top [NASA/GSFC/Arizona State University].

The Genesis Rock presented itself in situ on the top of a pedestal, "as though it had been waiting for someone to retrieve it." Scott & Irwin, aware on sight of the sample's potential scientific values, were careful to photograph the find both before and after retrieval [Mosaic of Genesis Rock "before" and "after" photos, assembled by David Harland/ALSJ].

Images of the Genesis Rock (left of the gnomon) just prior to collection and later on Earth, cataloged where it continues to be studied extensively at the Lunar Sample Bldg. at the Johnson Space Center in Houston. [NASA].

EVA 3: Station 9A - Observations of Hadley Rille

The last EVA allowed the crew to explore the edge of Hadley Rille. Pans at Stations 9 and 10 show two different craters the crew visited; one of which is a fresh crater with a blocky texture. 10Station 9A was a terrace that allowed Scott and Irwin a chance to peer down into the rille, which is approximately 1.3 km wide and 400 m deep along most of its length.

The crew was able to observe and photograph bedrock along the upper part of the western rille wall. Test pilots by profession, the crew went through extensive geology training so that they could communicate their observations effectively and efficiently to the Science Backroom in Houston, Texas. Most of us are familiar with different historic phrases from various Apollo missions. What is sometimes forgotten is that there was also a great deal of science being accomplished and discussed. Field geologists normally have a field notebook to write down and draw their observations in, but on the Moon everything has to be described verbally. Here is an example from Commander Scott's geologic description of the rille wall at this location and one of the images that corresponds with it. Compare his description with the photograph and this panorama.

165:22:50Scott: I can see from up at the top of the rille down, there's debris all the way. And, it looks like some outcrops directly at about 11 o'clock to the Sun line. It looks like a layer. About 5 percent of the rille wall (height), with a vertical face on it. And, within the vertical face, I can see other small lineations, horizontal about maybe 10 percent of that unit.

165:23:26 Scott: And that unit outcrops (at various places) along the rille. It's about 10 percent from the top, and it's somewhat irregular; but it looks to be a continuous layer. It may be portions of (mare basalt) flows, but they're generally at about the 10-percent level. I can see another one at about 12 o'clock to the Sun line, which is somewhat thinner, maybe 5 percent of the total depth of the rille. However, it has a more-well-defined internal layering of about 10 percent of its thickness. I can see maybe 10 very well-defined layers within that unit.

Outcrop of basaltic lava exposed along the western wall of Hadley Rille. Photographed from Station 9A. Letters point to rocks seen in the LROC NAC frame below. Apollo 15 image AS15-89-12115 [NASA].

The same outcrop photographed by Apollo 15, along the western wall of Hadley Rille as shown above, from an "aerial" perspective in this sample of LROC NAC frame M111571816RE. The letters point to the same rocks in the image taken from the ground in 38 years, 2 months and 28 days earlier. (The outcrop is ~75 m long.) [NASA/GSFC/Arizona State University].

The high resolution imagery from LROC allows us to retrace the steps of previous Apollo missions. Compare the Apollo 15 surface panoramas at the different stations with the LROC images to see if you can locate some of the individual rocks and outcrops seen in both perspectives.

Future crews that explore Hadley Rille and the Apennine Mountains could continue where Apollo 15 left off. Combining our previous exploration experience at the site with new remote sensing data sets, a new mission could explore the massifs to the north, additional sites along Hadley Rille, as well as revisit any of the Apollo 15 stations.

Friday, April 16, 2010

During a carefully staged appearance at Kennedy Space Center yesterday, President Barack Obama rolled out his plans for the U. S. space program. Although there weren’t many surprises (the White House Office of Science and Technology, under the direction of John P. Holdren, had released a fact sheet days earlier outlining details), one startling part of the speech was that we are abandoning the Moon as a goal. Though hinted at in several statements by people around the President, including NASA Administrator Charles Bolden and Apollo 11 Astronaut Buzz Aldrin, a path away from human return to the Moon is now officially the direction of Obama’s space policy.

Given the topic of this blog, it shouldn’t surprise many of you to learn that people are calling and writing me, asking for my reaction to the new policy. Although it wasn’t much of a surprise, it is disappointing to me, but not for the reasons you might suspect.

"Given the real and potential benefits of lunar return, the question is no longer “Why the Moon?” but “Why bypass the Moon?” I’m glad that “Buzz has been there” but that fact is irrelevant to either the value or the desirability of lunar return."

The speech detailed aspects of the administration’s new space budget, which will eliminate Project Constellation, contract with commercial entities for human transport to LEO, and spend money for development of new technology so as to “revolutionize” our access and capabilities in space. The Moon was finally mentioned near the end of the speech and I felt it would be fitting to use the President’s own words as the title for this post, and then give my views of the Moon’s place in the template of space exploration.

I’ve heard the “been there” line many times since 2004 when President George W. Bush announced the Vision for Space Exploration, so hearing it one more time was not a particularly jarring experience. But stop for a moment to consider exactly what President Obama said. Lunar return critics give many reasons to NOT go to the Moon: they think that it’s scientifically uninteresting, it doesn’t contain what we need, it will turn into a money sink (preventing voyages to many other destinations in space – perhaps one on their list), that there are more pressing needs here on Earth, and I’m sure others that I haven’t yet heard. But this new space policy rationale is unique and carries with it different and significant implications for our nation’s exploration of space.

We have now added a new requirement for U.S. space missions – we must go to a place never before visited by humans. Of course, some will argue that such a concept is implicit in the word “exploration” but until recently, exploration encompassed a much wider concept where exploration was followed by exploitation and settlement by many people from many walks of life using many different skills toward a myriad of goals. I wonder if supporters of this new space policy have stopped to consider the implications of the “not been there” requirement. The new meaning of exploration contains within it the seeds of its own termination: after you’ve touched the surface, planted a flag, and collected some rocks or deployed an instrument, that destination is “done.” Or does such a formulation apply only to the Moon?

One of the biggest criticisms hurled at Project Constellation is that it is largely a grandiose repeat of the Apollo explorations of the Moon undertaken over 40 years ago. Certainly, as had been outlined by NASA, lunar return consisted of sortie missions that landed crews all over the Moon to do local field exploration. Such a mission template is indeed Apollo writ large. But that is not and was never the intent of lunar return under the Vision for Space Exploration which is now under assault. Constellation was largely NASA’s rocket development program, while the Vision for Space Exploration was strategic direction outlining a sustainable lunar return, whereby we would bootstrap our way “beyond” by learning how to use the resources of the Moon and other bodies.

So let me respond to the President’s new plan by reminding the readers of this column why the Moon is our goal and of its significance and value to space exploration.

It’s close. Unlike virtually all other destinations in space beyond low Earth orbit, the Moon is near in time (a few days) and energy (a few hundreds of meters per second.) In addition to its proximity, because the Moon orbits the Earth, it is the most accessible target beyond LEO, having nearly continuous windows for arrival and departure. This routine accessibility is in contrast to all of the planets and asteroids, which orbit the Sun and have narrow, irregular windows of access that depend on their alignment with respect to the Earth. The closeness and accessibility of the Moon permit modes of operation not possible with other space destinations, such as a near real-time (less than 3 seconds) communication link.

"The new meaning of exploration contains within it the seeds of its own termination: after you’ve touched the surface, planted a flag, and collected some rocks or deployed an instrument, that destination is “done.” Or does such a formulation apply only to the Moon?"

Robotic machines can be teleoperated directly from Earth, permitting hard, dangerous manual labor on the Moon to be done by machines controlled by humans either on the Moon or from Earth. The closeness of the Moon also permits easy and continuous abort capability, certainly something we do not want to take advantage of, but comforting to know is handy until we have more robust and reliable space subsystems. If you don’t believe this is important, ask the crew of Apollo 13.

It’s interesting. The Moon offers scientific value that is unique within the family of objects in the Solar System. The Moon has no atmosphere or global magnetic field so plasmas and streams of energetic particles impinge directly on its surface, embedding themselves onto the lunar dust grains. Thus:

The Moon contains a detailed record of the Sun’s output through geological time (over at least the last 4 billion years). The value of such a record is that the Sun is the principal driver of Earth’s climate and by recovering that detailed record (unavailable anywhere on the Earth), it can help us understand the details of solar output, both its cycles and singular events, throughout the history of the Solar System. Additionally, because of the Moon’s ancient surface and proximity to the Earth, it retains a record of the impact bombardment history of both bodies. We now know that the collision of large bodies has drastic effects on the geological and biological evolution of the Earth and occur at quasi-regular intervals. Because our very survival depends on understanding the nature and history of these events as a basis for the prediction of future events, the record on the lunar surface is critical to our understanding.

A radio telescope on the far side of the Moon can “see” into deep space from the only platform in the Solar System that is permanently free from Earth’s radio noise. The Moon is a unique, rich and valuable scientific asset.

It’s useful. In my opinion, this is the most important and pressing argument for making the Moon our first destination beyond LEO. Because of the detailed exploration of the Moon undertaken during the last 20 years, we have a very different understanding of its properties than we did immediately following Apollo. Specifically, the Moon has accessible and immediately usable resources of both energy and materials in its polar regions, something about which we were almost completely ignorant only a few years ago. For energy, both poles offer benign surface temperatures and near-permanent sunlight, as the lunar spin axis obliquity is nearly perpendicular to the plane of Earth’s orbit around the Sun. This relation solves one of the most difficult issues of lunar habitation – the 14-day long lunar night, which challenges the design of thermal and power systems. In addition, once thought to be a barren desert, we have recently found that the Moon contains abundant and accessible deposits of water, in a variety of forms and concentrations. There is enough water on the Moon to bootstrap a permanent, sustained human presence there. Water is the most important substance to find and use in space; not only does it support human life by its consumption and provision of breathable oxygen, in its form as cryogenic liquid oxygen and hydrogen, it is the most powerful chemical rocket propellant known. A transportation system that can routinely access the lunar surface to refuel, can also access all of cislunar space, where all of our national strategic and commercial (and much of our scientific) assets reside (many satellites reside above LEO and are inaccessible for repair). Such a system would truly and fundamentally change the paradigm of spaceflight and can be realized through the mining and processing of the water ice deposits near the poles of the Moon. Space exploration should be a driving force in our economy not merely a playground for scientists or a venue for public entertainment.

Given the real and potential benefits of lunar return, the question is no longer “Why the Moon?” but “Why bypass the Moon?” I’m glad that “Buzz has been there” but that fact is irrelevant to either the value or the desirability of lunar return. By proposing to eliminate the Moon as a destination, the President has fundamentally altered the societal value of the space program in a significant and qualitatively different way.

If our new space program is to be made into a simple instrument of public spectacle (“cheap thrills” and “colossal feats,” as variously reported by news columnists) with each new mission requiring a “series of ‘firsts’ to engage and excite the public”, it will no longer have any more real long term benefit to our national security and wealth than did the bread and circus shows that heralded the demise of ancient Rome. Yes, there were and will be some exciting spectacles. And when such events are finished, people turn away and go home – none the wiser, none the richer, and none the better off. We won’t be staying at any destination long enough to fully characterize it and use what it has to offer.

Is this the kind of space exploration we want?

The seeds of the termination of our national space program were planted yesterday in Florida.

Earlier this week, Nancy Atkinson at UniverseToday brought to our attention some outstanding value-added work by Nathanial Burton-Bradford using dual LROC narrow-angle camera frames of Apollo landing zones, e.g., "Tranquility Base," imaged from slightly contrasting perspectives. It's raw material for his stunning 3-D views, posted on Flickr. Above, the year-old astonishing views of Buzz Aldrin's short stroll behind Eagle to the rim of West Crater is even clearer undisturbed and details like the Lunar Module foot pads stand out more readily than in the original releases. Opportunities abound for similar work, something already well demonstrated by the LROC team itself particularly in surveys of the Apollo 14 LZ.

Above, still missing is Apollo 11 U.S. flag, blown free, according to Buzz Aldrin when he and Armstrong departed. Such "value-added" views have shown the potential for using LROC NAC frames for further identifying compositional differences. Can you see any traces of something downrange from Eagle in Burton-Bradford's image of the Apollo 11 LZ that may, in fact, be the rudely treated original American flag?

"Foot-pads, foot prints and flag," etc. ? Well, perhaps not the First Flag at Tranquility Base (above). U.S. flags are identifiable in the LRO surveys of subsequent Apollo landing sites, but Buzz Aldrin's contention that the first of the six United States flags on the Moon was blown clear by the lunar module ascent stage exhaust is safely confirmed.

Film of their lift off, from on-board Eagle through Aldrin's view port showed the flag, planted too close those First Steps, was suddenly engulfed in a hurricane wind of hot gases as Armstrong & Aldrin started their ascent, July 21, 1969.

The camera was not as fast as Aldrin's eyes, of course. There are some still holding out hope that an obvious swirl of debris in subsequent frames seen blowing down stream held enough red reflecting foil and other fragments that might have been easily mistaken for the object Aldrin insists was the American flag; already a 100 meters off and rapidly tumbling away.

The flag's absence at Statio Tranquillitatus is a notable contrast with LROC surveys of the last American station on the Moon. The flag set up by Cernan & Schmitt in Taurus-Littrow valley, of course, was seen to be intact in the live television sweeps of the Apollo 17 station for hours after their departure. Next to nothing appears to have changed over the 38 years since.

But looks can be disturbing. Have the colors bleached to gray, as some believe? After LRO, approaching the artifacts, which have now become important Long Duration Exposure experiments, will require caution and planning, if any record of dust fallout, specific to each artifact's exact place on the Moon, valuable and fragile information, can be preserved.

The "best practice" approach should be from the ground and from a distance (probably greater than might be generally believed).

Today, we understand at least some of the dust uplifted by powered descents, like those of the Apollo missions, as well as some of the dust and debris "disturbed" by their departure actually reached escape velocity. Many more microscopic grains were propelled into ballistic paths at least as high as the Apollo CSMs standing by in orbit.

The first American flag was too heavy to have been blown so high and far, like nearly anything likely to be visible to the naked eye. The plume of exhaust gases rapidly dissipated, temporarily increased the weight and composition of the lunar exosphere by an appreciable percentage, as did each depressurization of the LM prior to EVA.

Tumbling along, losing energy fast, Apollo 11's flag is probably well within a half kilometer of the Apollo 11 descent stage. If it has been located, neither Dr. Robertson's team nor anyone else studying the LROC photography has announced it. Like finding Luna 9, the first soft-lander sent by the Soviets, it has already been photographed though, but it remains lost in crowded fields similarly-sized objects at the edge of resolution capabilities even of LROC's narrow angle camera.

(Some of us are never satisfied.)

Recent high-resolution photography from NASA's Lunar Reconnaissance Orbiter continues to dazzle, living up to the best expectations. A month after a first public release of nearly 40 terabytes of data, in the form of over 108,000 photographs, LROC has provided more than enough opportunities for original interpretations.

The Lunar Reconnaissance Orbiter Camera (LROC) team at Arizona State University, lead by Dr. Mark Robinson has somehow wrestled it all into a searchable online metadata search engine, requiring little more than a cursory understanding of the Moon and where things are there to be useful.

The lunar surface only seems as straight forward an object for study, with little atmosphere and presenting its well-illuminated surface unchanged over Ages tallied in the billions of years. But the truth is more magnificent. What Shakespeare summed up nicely as the "inconstant Moon" is the Rosetta Stone of our Solar System.

Useful as a functional 3-D image, with or without the 3-D glasses (though they help), Nathanial Burton-Bradford's value-added comparative contrast of two slightly differing perspectives of the immediate landing site of Apollo 17, each photographed by the LRO narrow-angle camera (NAC) flying in low lunar orbit on board NASA's Lunar Reconnaissance Orbiter.

A still (below) taken from the dramatic, poignant live feed from the suddenly-lonely, remotely-operated color television camera on Apollo 17's lunar rover, in the minutes after the Cernan & Schmitt's departure, December 14, 1972. Recent Narrow-Angle Camera (LROC) images from NASA's Lunar Reconnaissance Orbiter demonstrate Apollo-era artifacts on the Moon, including Apollo 17's lunar module descent stage, after more than 450 blistering lunar days and stone cold lunar nights, seem placidly undisturbed [NASA/A17-LSJ].

A sinuous rille created by a lava flow snakes around the base of a massif in the Prinz-Harbinger region on the Moon. Image width is 1.46 km, from LROC NAC frame M102429075L [NASA/GSFC/Arizona State University].

When choosing a site for future human or robotic lunar exploration, access to a diversity of geologic features in the area is taken into consideration. The Prinz-Harbinger area is a Constellation region of interest because there is a concentration of sinuous rilles, massifs, and mare filled impact craters, as well as potential lunar resources (Fig. 1). The topography is reminiscent of the Apollo 15 landing site where there is a rille bound by nearby massifs. Rilles provide information on lava flow processes that created the lunar maria and provide an opportunity to collect samples from exposed bedrock. The massifs at this site are related to the Imbrium impact basin and have a different lithology from the surrounding mare units based on multi-spectral data. The regolith contains pyroclastic deposits from volcanic eruptions that could be used for in situ resource utilization (ISRU) by future crews.

The use of local resources not only reduces the cost of exploration, but also enables explorers to increase their time on the surface and make even more discoveries.

Figure 1. Apollo 15 image AS15-M-2081 of the Rimae Prinz region. White boxes show the coverage of the Constellation Region of Interest (CxP ROI) at distances of 10, 20, and 40 km surrounding the rille. Footprint coverage of the NAC frame is given for context [NASA/Arizona State University].

The massif featured in Fig. B is ~600-700 m in relief, while other massifs in the Montes Harbinger chain are up to 2000 m in relief (Fig. 1). Note the elephant texture on the southern slopes changes to a smoother darker texture before the bottom of the hill (arrows in Fig. 2). This shows that the base of the massif was partially buried by lava flows related to the volcanic activity and rille formation in the area. The rille adjacent to the massif is ~450-500 m wide and a few 100 meters deep. The CxP ROI is centered on a gap in the rille, which could be a roofed over portion that forms a lava tube. Lunar lava tubes, while potentially difficult to access, are of high interest for both their geologic information about the emplacement of lava flows and their potential as a natural place of refuge and possibly even habitation for future explorers.

Figure 2. A lunar rille forms at the base of the massif in the Constellation Region of Interest (CxP ROI). Arrows point to location along massif possibly covered by lava flows, due to the lack of 'elephant skin' texture on this part of the hill slope. LROC NAC M102429075L [NASA/GSFC/Arizona State University].